The aim of this project is to further elucidate the influence of behaviors during infancy and early childhood on the development of adiposity to the age of six years. Research evidence suggests that there are two developmental periods before puberty during which marked changes in adiposity occur, the first during infancy, and the second between three and six years of age. This suggests that an interaction may occur between early and later behaviors to determine both the development of adiposity and the risk for later obesity. In a previous study we found that vigorous feeding style, denoted by high pressure suckling during the first month of life, predicted degree of adiposity at one, two, and three years of age. In addition, evidence suggested that duration of breast feeding and time of introduction of solid food were important factors determining later adiposity. To extend these findings, 200 infants will be followed from birth to six years of age with measures of suckling style, early feeding practices, childhood eating style and food intake, and childhood activity levels. Measures of genetic and socioeconomic influences will also be obtained. Outcome variables including Body Mass Index and skinfold measures will be obtained at regular intervals. Relative distribution of body fat (abdominal/hip ratio) will also be obtained since this factor has been shown to be related to cardiovascular risk factors in both older children and adults. Clarification of the interaction between early and later behaviors affecting the development of adiposity should lead to a better understanding of the way in which the environment and behavior influence the progression of adiposity and the development of obesity. Elucidation of behavioral risk factors for the development of excess adiposity, and delineation of the timing of these influences, may also enhance our ability to develop effective programs to prevent the development of obesity.